The golden langur lives only in Bhutan and adjacent Assam. It probably evolved in geographic isolation on the western side of the Manas river. On the other side of the river is its close cousin ...

Popa langurs, or Trachypithecus popa, belong to the Trachypithecus genus of Old World primates that live throughout Southeast Asia. The ‘Old World’ refers to the primates native to Africa ...